Doubt about corporation approval. Please help.

We are trying to build a house in our empty space and checking on getting the corporation approval. Lets say if I have 1750 sq ft and building a house there, according to chennai corporation we have to leave 5 ft open space on all sides. So after all these empty space only 1000 sq ft is left for building the house which is 55% of 1800 sq ft. How is this acceptable? So can we deviate from this and build a house, lets say by keeping 2 ft instead of 5 ft on all sides? Will any problem arise in the future if we deviate from the approval plan? Has anybody done like this? Almost most of the buildings in chennai seems like they didn't follow these rules. Is it ok to do so?